Portable tube bending tool



March 22, 1949. G. E. FRANCK PORTABLE TUBE BENDING TOOL Filed Jul y 15', 1944 IN V EN TOR.

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Patented Mar. 22, 1949 2,464,800 PORTABLE TUBE BENDING TooL George E. Franck, Riverside, Ill'., assignor to The Imperial Brass Manufacturing Company, Chicago, 111., a corporation of Illinois Application July 15, 1944, Serial No. 545,095

I. Myinvention relates to a hand service tool and particularly a, tool for bending tubing. The invention has great utility in the bending of thinwalled metal tubing made of such materials as copper, brass. and. aluminum.

Amongv the objects of. my invention is to provide a new and improved bending tool for tubing. in. which all of the parts are permanently attachedt'ogether so that they cannot inadvertentlybe separatedone from another.

Another object of my invention is to. provide a.- new and improved. bending tool for. tubing whichv is. compact in. its construction by reason of the elimination of excess parts and whichv is efliciently designed from the point of view of operation.

Still another object of my invention .is .to provide anew and improved bending tool consisting of two-parts loosely attached together so that they can be opened up for reception of tubing without being. completely separated one from the other and which can then be engaged in a bending position with respect to each other and the tubing for periorming the necessary bending operation; there being included also among the objects the provision of a bending tool which can be released from the tubing at any point" in the bending operation.

Among the further objects of my invention is to provide a bending tool including lever arms which can be released from the tubing at any point in the bending operation.

Among the further objects of my invention is to provide a bending tool including lever arms which are grasped by'hand for making the bend wherein the lever arms at the start of the bend are extended one with relationship to the other "in: the most appropriate position for exerting proper leverage" and control over the tool and in such a manner that effective leverage and control is maintained throughout all positions duringith'e making of a-bend of 180.

A further object also of my invention is to provide a bending tool comprising two parts permanently attached together but which can be released a limited extent for reception of the tubins and then engaged in tube-bending relationship "wherein the connecting means between the two parts is so arranged that the pressure ex.- erted during the bending operation tends to hold the parts more tightly in proper bending relati'onship.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various. parts. of my de- 3 Claims. (CI. 81-15) vice whereby the objects contemplated are attained, as hereinafter more fully set forth, point.- ed out in my claims and illustrated in the accompanying drawings, in which:

Figure 1 is a side view of the bending tool with theends of the bending levers broken away showing in solid lines the tool and a tube engaged as for starting a bend and in dotted lines the position ofthe bending levers separated a limited extent. for reception of a tube.

Figure 2 is a side View of the reverse side of Figurel.

Figure 3 is an end View. taken on theline 3-'-3 of Figure 1.

Figure 4 shows the relative position of the parts of the. tool at the completion of a bend.

Figure 5 shows the parts of the tool to a smaller scale in the position occupied at completion of a bend.

In the. bending of thin-walled tubing for ordinary commercial purposes such as for installation of refrigeration lines and for fuel and oil lines in automobiles and aircraft it is necessary to employ a bending tool which is convenient and compactly arranged and at the same time one which can successfully bend thin-walled tubing without crushing the tubing or distorting it unduly in its cross-sectional shape. of. a wide variety have been devised in the past but these for the most part are bending tools not meant to be carried around in a service kit. There have likewise been tools directed primarily to the purpose of bending hard-walled pipe and they have failed to have incorporated in them the requirements necessary to prevent a bending tool .fromdistorting and crushing relatively soft thinwalled tubing. Somefew bending tools have been devised. for bending tubing but those which have been available heretofore have lacked the simplicity and convenience needed in a tool which can be readily carried about in a service kit and quickly put to use by mechanics with limited skill, especially in relatively inaccessible corners where machinery has to be installed.

In the drawings there is shown a. bending block l-ll about which the tube is to be bent. This-block is in the form of a substantially circular disc of appreciable thickness which. has asemi-circular groove l2 having a diameter equal to the size of the tubing to be bent extending around the edge of the. bending block. There is a flat'surface M on one side of the bending block. and-a handle iii threadedly engages the bending block atthe fiatside. Aclam-p I8 for holdingza length oftubing- 20 is mounted rotatably-upon the handle Pipe benders' 16 at a point immediately adjacent the bending block and is held in this position by a shoulder I! on the handle. The clam-p has a somewhat hookshaped slot 22 as best seen in Figure 3, and may be mounted to rotate axially about the handle. The surface of the hook which engages the tubing is relatively long so that pressure developed during the bending operation will not mar or dent the portion of the tube engaged by the clamp.

Cooperable with the bending block and handle is a bending lever 26 which has a relatively large streamlined head 28 provided with a flat side piece 30 which lies flat against the rear face of the bending block as viewed in Figure 1. The flat side piece is held rotatably against the bending block :by means of the large head 32 of a shaft 34 which is centrally disposed relative to the bending block. As shown in Figure 3 the shaft 34 is riveted over in order to permanently secure it in fixed position upon the bending block.

The bending lever 26 is provided with a forming element 36 having therein an elongated semi-circular groove 38 having substantially the same cross-sectional diameter as the groove l2 in the edge of the bending block.

In the fiat side piece there is provided an arouate slot 40 terminating in rounded ends 40' and 40 of a radius just slightly larger than that of the shaft 34. The balance of the slot is of a uniform width slightly greater than the diameter of the shaft 34 so that the shaft may slide freely from one end of the slot to the other while held therein by the head 32. While the slot 40 is here shown as arcuate, which is a preferred form, it need not take that precise form so long as the halves of the slot are disposed at an angle to one another,

The position of the slot 40 relative to the forming element 36 is such that when the shaft 34 is in the end 40 the edges of the forming element 36 just clear the periphery of the block ID. The end 40" of the slot is located beyond the end 40' in an obliquely forward direction. By forward direction is here meant from the handle portion of the lever 26 toward the head 28. Thus the slot 40 extends generally in the same direction that the head extends from the handle portion of the lever 26 and with the side of larger radius nearer the groove 38. With this mode of coupling, the cooperating elements are separated for reception or discharge of a piece of tubing by relative generally longitudinal movement of the lever 26, and are returned to operative bending position by similar movement in the opposite direction. Only a slight movement of a fraction of an inch is necessary and no swinging of the lever 26 is required to receive or discharge a piece of tubing, and this is true regardless of the relative angular positions of the members l6 and 26.

About the exposed face of the bending block a series of numerals show intervals from to 180 and are cooperable with an indicating mark .42, so that the coinciding of the indicating mark with one of the numerals will immediately show the extent to which the tube has been bent. See

for example Figure 4 Where the tube has been bent through an angle of 90".

In operation the parts of the tube-bending tool are initially separated one with respect to the other, as shown in Figure 1 by the handle and bending block in solid lines and the bending lever in dotted lines. The shaft 34 is now in the end 40" of the slot. Where the parts of the bending tool are separated to this extent there is sufficient room between the edge of the forming element 36 and the edge of the bending block In so that the tube can be inserted by lateral movement between them and thereafter be positioned within the groove l2 and the bending block. After the tube has thus been inserted the clam-p I8 can be pivoted about until the hooked portion engages the tube 20, as best shown in Figure 3. Note that the side piece 30 now lies on one side of the tubing and the clamp i8 on the other side.

After the tube has thus been hooked in place the bending lever is moved into bending relationship with the bending block. This is accomplished by means of sliding the bending lever together with the flat side piece in a direction toward the bending block so that the shaft 34 slides from the end 40 of the slot 40 to the end 40 of the slot. When the shaft 34 has finally been received into the end 40' of the slot as just described, the bending lever 26 is then pressed into bending relationship so that the forming element 36 .bears against the tubing and at the same time presses the end wall of the slot against the shaft. By reason of the pressure acting in this way the tendency of the pressure exerted during the bending operation is to always press and maintain parts of the tool in bending relationship with the tubing.

As the bend continues to be made by rotating one handle about the other, the bend progresses as illustrated in Figure 4. This may extend to a 90 bend for example. If it is only a 90 bend which is desired the parts of the tool can be released by merely relieving the pressure upon the handle at that point and thereby permitting the shaft to slide from the end 40' of the slot shown in Figure 4 to the end 40" of the slot. This movement will separate the parts of the tool sufficiently so that the clamp can be removed and the tube extracted laterally from the tool.

Should a 180 bend be required the parts of the tool are rotated until they assume the relative positions shown in Figure 5. From this position also the parts of the tool are released in a manner similar to that described in Figure 4 and the tube released as previously described,

There has thus been provided a convenient and compact bending tool all in one piece which can be readily carried about in a servicemans kit and which is capable of making bends in tubing to any degree between 0 and 180, and which can be readily released from the tubing at any degree of l the bend.

Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure, or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention: I

1. A bending tool for tubing comprising a relatively stationary member including a bending block having a semi-circular grooved edge into which the tubing is bent, a handle extending from one side of the block and a rotatably mounted clamp for the tubing adapted to be swung into place over the tubing, and a relatively movable member including a bending lever having a handle, a flat extension on the lever on one side of the block having therein an arcuate slot rounded at its ends and of uniform width intermediate the rounded ends, means engaging the outside of the flat extension including a shaft at the center of curvature of the block extending beyond one side thereof and laterally through the arcuate slot and a forming element having a straight groove therein complementary in cross section to the groove in the block, said bending lever having an initial position wherein the f orming element is separated from the block a distance sufficient to permit insertion of a piece of tubing therebetween when the shaft is in one end of the arcuate slot and having a bending position with the respective grooves closely surrounding the tubing when the shaft is in the other end of the arcuate slot, the last named end of the slot being inclined so that. the center line thereof forms more than a 90 angle with a radial line perpendicular to the axis of the groove in the forming element, commencing with the radial line and measured in the direction of rotation of said forming element, to form a seat for said shaft during the bending operation.

2. A bending tool for tubing comprising a relatively stationary member including a bending block having a semicircular grooved edge into which the tubing is bent, a handle extending from one side of the block and a rotatably mounted clamp for the tubing adapted to be swung into place over the tubing, and a relatively movable member including a bending lever having a handle, a fiat extension on the lever on one side of the block having therein an arcuate slot rounded at its ends and of uniform width intermediate the rounded ends, means engaging the outside of the fiat extension including a shaft at the center of curvature of the block extending beyond one side thereof and laterally through the arcuate slot and a forming element having a straight groove therein complementary in crosssection to the groove in the block, said bending lever having an initial position wherein the forming element is separated from the block a distance suflicient to permit insertion of a piece of tubing therebetween when the shaft is in one end of the arcuate slot and having a bending position with the respective grooves closely surrounding the tubing when the shaft is in the other end of the arcuate slot, the first named end of said slot being inclined so that the center line thereof forms a small angle with a radial line perpendicular to the axis of the groove in the forming element to permit separation of the relatively movable and relatively stationary members by movement of the movable member generally radially of the bending block and without necessity for rotational movement of said movable member.

3. A bending tool for tubing comprising a relatively stationary member including a bending block having a semicircular grooved edge into which the tubing is bent, a handle extending from one side of the block and a rotatably mounted clamp for the tubing adapted to be swung into place over the tube, and a relatively movable member including a bending lever having a, handle, a fiat extension on the lever on one side of the block having therein an arcuate slot rounded at its ends and of uniform width intermediate the rounded ends, means engaging the outside of the fiat extension including a shaft at the center of curvature of the block extending beyond one side thereof and laterally through the arcuate slot and a forming element having a straight groove therein complementary in cross-section to the groove in the block, said bending lever having an initial position wherein the forming element is separated from the block a distance sufficient to permit insertion of a piece of tubing therebetween when the shaft is in one end of the arcuate slot and having a bending position with the respective grooves closely surrounding the tubing when the shaft is in the other end of the arcuate slot, the last named end of said slot being inclined so that the center line thereof forms more than a angle with a radial line perpendicular to the axis of the groove in the forming element, commencing with the radial line and measured. in the direction of rotation of said forming element, and the first named end of said slot being inclined so that the center line thereof approaches parallelism with the radial line perpendicular to the axis of the groove in the forming element.

GEORGE E. FRANCK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,631,916 Chambers June 7, 1927 1,824,026 Little Sept, 22, 1931 1,852,515 Haddock Apr. 5, 1932 2,127,185 Parker Aug. 16, 1938 2,171,907 Beehler et al. Sept. 5, 1939 FOREIGN PATENTS Number Country Date 417,656 Great Britain Oct. 3, 1934 

